The present invention relates generally to printed circuit cards, and more specifically to printed circuit card assemblies having controlled vibrational properties.
Rapid advances in technology and increasing consumer demand are driving manufacturers and suppliers of electronics systems to increase the population density of devices on circuit cards, and to populate the circuit cards with more powerful circuit devices. As both the number and power consumption of the circuit devices on a circuit card increase, more heat is produced in the card. Dissipation of these large amounts of heat require the use of more numerous, larger and more massive heat sinks.
The increased number and large mass of such heat sinks can significantly alter the vibrational characteristics of the circuit card assemblies on which they are mounted, by producing large displacements of the circuit card that can overstress various physical components on the circuit card assembly and lead to early failures. The size and location of these large displacements can be controlled primarily by a single heat sink that is very large, or by a distribution of heat sinks of varying sizes.
Failures due to vibration induced displacements can occur in different applications. Of particular concern are applications that experience a significant amount of vibration, such as those in mobile environments. Circuit card assemblies mounted in mobile environments often endure significant amounts of vibration, causing the circuit card assemblies to produce large displacements.
For the reasons stated above, and for other reasons stated below which will become apparent to those skilled in the art upon reading and understanding the present specification, there is a need in the art for a method and apparatus to control vibrational properties of circuit card assemblies.